Wiring device with grounding means



Nov. 13, 1962 R. o. WILEY WIRING DEVICE WITH GROUNDING MEANS Filed July10, 1959 INVENTOR Roy 0. WIIey W ATT' NEY WITNESSES dfiiidizd PatentedNov. 13, 1962 WERZING DEVEQE WITH GRQUNDING MEANS Roy 0. Wiley,Bridgeport, Conn, assignor to The Bryant Electric Company, Bridgeport,Conn, a corporation of Connecticut Filed July It), 1959, Ser. No.826,173 4 Claims. (ill. 339-14) 'Ihe present invention relates toelectrical wiring devices, and more particularly to receptacles in whicha grounding connection is provided.

In applications where electrical potentials of a value substantiallyabove ground potential are found to exist, it is often desirable in theinterest of safety to provide an electrical connection to ground fromany normally neutral structures which are likely to be contacted byoperating personnel. Such a connection, then, ensures that the mentionedstructures will continuously exist at ground potential and thereforecannot exist at any higher electri- 1 cal potential as a result of anycoupling with any other environmental structure having such a higherpotential.

I If, for example, a metallic casing or housing or other structuralmember for an electrical device is to be grounded, it is desirable thatsuch a grounding connection be made with the same motions that are madefor establishing other electrical connections for the electrical device.In such a case, it is common to make use of a grounding prong which isprojected, along with other or energizing prongs, from a terminal plugof the device and which is connected to the housing of the device. Whenthe plug is inserted in a receptacle for connection to an electricenergy source, the grounding prong is then engaged by a contact which isprovided in the receptacle and which is permanently connected to ground.

'Ihus, each'time the electrical device is connected to the receptacle, aground connection for the housing of the device is assured provided thegrounding prong and the grounding contact of the receptacle make areliable contact and provided the grounding contact of the receptacle isreliably and permanently connected to ground. The present invention isdirected toward these last-mentioned provisions.

It is therefore, an object of the invention to provide a novel wiringdevice in which a reliable ground connection is provided.

It is another object of the invention to provide a novel wiring devicefor which a grounding connection is provided integrally on a conductivesupport member for the wiring device.

It is a further object of the invention to provide an electricalreceptacle in which grounding means are reliably yet economicallyincluded with the further advantage of being readily accessible forestablishing a permanent grounding connection thereto.

These and other objects of the invention will become more apparent uponconsideration of the following detailed description of an illustrativeembodiment of the invention in relation to the accompanying drawings, inwhich: 7

FIGURE 1 is a top plan view of an assembled electrical receptacleconstructed in accordance with the principles of the invention;

FIG. 2 is a bottom plan view of the receptacle shown in FIG. 1 with onlyone terminal inserted therein;

FIG. 3 is an exploded isometric view of a mounting member for thereceptacle in FIG. 1 and for which grounding means are shown in apreassembled position.

In accordance with the broad principles of the invention, a wiringdevice comprises an integral housing that receives and readily engagesterminal members and a mounting means on which prong engaging contactsand a permanent ground connecting member are provided for reliable anddurable operation. Although the illustrated electrical receptacle willbe described to point out the invention, other wiring devices havingmodified structures will obviously appear to those who are skilled inthe art to which the invention belongs without departing from theprinciples of the invention. Accordingly, in view of this consideration,the detailed description of the illustrative embodiment of the inventionwill now follow.

With reference to FIGS. 1, 2 and 3, an electrical receptacle 8 comprisesan elongated housing member 1%, amounting member or yoke 12, andterminal members 14. The housing 10 is integrally molded from a materialhaving insulative and mechanical properties suitable for the intendedapplication of the receptacle 8. The structure of the housing It} issuch that it can support and insulate the terminals 14 and,additionally, can support the mounting member 12 whereby the cooperativeassemblage forms the receptacle 8 which then functions in a fashion tobe explained more fully hereinafter.

The housing it) includes two elongated terminal receiving piers 16having a channel 13 (FIG. 2) therebetween. The piers 16 are spanned byfacedportions 2i) that can support electrical plugs (not shown) havingprongs for insertion into the receptacle it. The mentioned channel 18serves to receive the mounting member 12 in a manner which will becomemore apparent later in the description.

Structural walls 22, 26, 28 and 3d are formed to present substantially arectangular parallelepiped geometry for each of the piers 16. Within thewalls 22, 26, 2S and 3% is a chamber 24 for the reception of theterminal 14. A particular description of the principles which govern theengagement of the terminal 14 by the pier l6 and the functionalcooperation between these members is fully set forth in a copendingapplication of S. A. Mason, entitled Wiring Device, filed July 10, 1959,Serial No. 826,266, and assigned to the present assignee. It willsufiice to note here that, after engagement of the terminal 14 by thepier 16, an electrical contact or blade 32 on each end of the terminal14 is positioned within the pier 16 in a manner permitting engagementwith a prong of an inserted plug, reference to which has already beenmade.

The end wall 26 is provided with a projecting ridge 34ialong its inwardlateral edge for engagement with the mounting member 12 during assemblyof the receptacle 8. The other end wall 23 of each of the piers 16 issimilarly provided with a projecting ridge 36 for engagement of themounting member 12. Additionally, a transversely extending groove 38 isprovided in each wall 23 for guidance and retainment of a portion of themounting member 12. This latter relation will be more fully understoodupon detailed consideration of the mounting member 12.

The Wall 30 on the inner side of each of the piers i6 is provided withtransversely extending ridges 46 to serve as fulcrum points forgrounding contacts, to be described hereinafter, on the mounting member12. Additionally, a longitudinal midsection 42 of each side wall 30 isgenerally recessed from the plane of the side wall 3t} in order toprovide for reception of a corresponding midsection 43 of the mountingmember 12. Themidsection 42 also provides for stable engagement of themounting member 12 by means of transversely extending ridges 44.

The mounting member 12 is most advantageously viewed in FIG. 3. It is anelongated member constructed from a conductive but resilient material,such as sheet steel, and adapted to be supported, as previouslyindicated, by the housing 10. An elongated strip 46, with the broadenedmidsection 48, to which reference has previously been made, constitutesa substantial part of the length of the mounting member 12. Adjacenteach end of the mounting member 12, a riser 56 extends upwardly to alongitudinally projecting car 52. There is an'aperture 54 for passage ofa mounting screw (not-shown) in eachof the projecting cars 52. What isgenerally denoted as an end section 56 or 53 extends from the strip 46to a lower portion of the riser 59 adjacent each end of the mountingmember 12. Apertures 69 for passage of a grounding prong, referred tohereinbefore, are provided in the end section 56 and, additionally, inthe midsection 48 of the strip 46. The midsection 48 also includes anopening 62 through which a suitable fastener may be passed for securinga faceplate (not shown) over the receptacle 8 when it is mounted.

Each of the end sections 56 or 58 additionally has inwardly projectingcantilever tabs 64 for engagement with the. housing 1%. The endsection58 .has transversely extending arms66 of which the ends areinterconnected by acrossplate 68.. The crossplate 68 can beattached tothe ends of the arms 66 by any convenient means, as by welding portions67 of the crossplate 68 to sides 69 of the arms 66 or, in certaininstances, can even be integrally formed therewith. When the crossplate68 is attached to the arms 66, an end portion or extension 70 of thecrossplate 68 projects beyond the lateral limit of each arm 66. Each ofthe crossplate end extensions '70 then accede to the character ofv arailing which is to be guided into the previously-mentioned pier grooves38' during assembly of the wire device.

A grounding contact 72 is formed from resilient wire into a shapesubstantially as shown in FIG. 3 and is attached to the mounting member12 adjacent each of the grounding prong apertures 69 so that thegenerally U-shaped configurations of the aperture 60 and of thegrounding contact 72 are in alignment. This attachment can beaccomplished in any of a number of ways, but, in the embodiment shown,it is preferably made by welding.

Prior to any assembly of the receptacle'8 the grounding contacts 72 andthe'crossplate 68 can be united with the bodyof the mounting member 12as indicated above. An assembly of the receptacle 8 can then beaccomplished by first inserting a terminal 14 in each of the piers 16 ofthe housing in a manner fully described in the previously mentionedcopending application. The mounting member 12 can then be assembled withthe housing 10 in a manner such that the mounting member strip 46 passesinto the channel 18 betwen the piers 16 of the housing 10. When themounting member 12 is inserted to a position against under surfaces 74of the faced portions 20, engagement of the mounting member 12 with thehousing 1% can then be made, desirably by applying an impulsive force tothe cantilever tabs 64 and thereby inbedding the tabs 64 in theprojecting ridges 34 and 36 of the pier end walls 26 and 28. However, incertain cases such as those instances pointed out in the mentionedcopending application, the mounting member 12 can be engaged with thehousing 10 through frictionalcooperation without the application of animpulsive force. Additional stability, contributing to engagementbetween the mounting member 12 andthe housing 10; exists between themounting member strip -46 and the side wall ridges 40 and 44.Furthermore, the end extensions or railings 70 of the crossplate 68 willhave been guided into a position within the grooves 38 of the end walls28. This latter relationship provides, among other things, lateralstability for the crossplate 68 and the arms 66. It is to be noted,however, that the crossplate 68 can be attached to the mounting member12'after' the mounting member 12 is assembled with the housing 10.

With the mounting member 12 fully inserted, the

' grounding prong apertures 60 of the mounting member 12 are inalignment with grounding prong openings 76 provided in the facedportions 20. A terminal screw 77 can be passed into an opening 78 of thecrossplate 68 as means for engaging a wire or other conductor maintainedat 2. ground potential. It will,...accordingly, be realized that when agrounding prong makes electrical contact with the mounting membergrounding contact 72 an electrical connection will exist between theprong and ground.

When the receptacle 8 'is-placed in use, the aforementioned plug with agroundingprong can be inserted into the receptacle 8 so that" thegrounding prong passes through the opening 76 of one of the facedportions 26.

There are ordinarily two-remaining plug prongs which then pass throughfaced portion slots 80 into engagement with the terminal blades32'located within the housing '26. Upon passage of the grounding prongthrough the faced portion opening 76 and consequently through and beyondthe mounting member aperture 69 in alignment therewith, a reliableelectricalconnection is made between the prong and the mounting membergrounding contact 72. This connection is occasioned by legs82 of the:contact 72 which are sufficiently resilient to exert a clamping forceupon the grounding prong. ,A full description of the relationships whichoperate to provide this connection appears in a copending application ofC. Smith,-en- Y titled Wiring Device, filed November 29, 1957, SerialNo.

699,765, was assigned to the present assignee; It will be noticed,however, that the present construction-of the grounding contact 72 issuch that a point of stress concentration exists at each portion 84 0fthe-contact 72 which is adjacent the fulcrum ridges -46 of the housing10.

With the concentration of any existing stress at these points of thegrounding contact, little or no stress is transmitted to bight 86 wherethe grounding contact 72, in this example, is welded to the mountingmember 12.

Although the receptacle, described herein is not shown to have aninsulative cover for the underside of the piers 16, such a cover can beprovided in accordance with the principles of an invention described inanother copending application of S. A. Mason, entitled Wiring Device,filed July 10, 1959, Serial No. 826,218, and assigned to the presentassignee. It remains to be noted that the construction of the receptacleis certainly economical for the component parts of the receptacle areminimized in number and are simplified in structure. This economy ofcon-- struction, however, does not impair the reliability of anyoperation of the receptacle. It is particularly noteworthy that areliable grounding connection is" always available for the receptacle. V

In the fo'regoingdescription, an embodiment of the invention, as alreadyindicated, has been described for illustrative purposes only.Accordingly, it is desired that the invention be not interpreted'asbeing limited to the described embodiment, rather it is desired that itbe accorded an interpretation consistent with the scope and- V spirit ofits broad principles.

. said prong is inserted therebetween, said mounting mem- V What isclaimed is: 7 r 1. An electrical wiring device adapted for reception ofa plug having a grounding prong, said device comprising 7 an elongatedhousing having spaced projecting portions extending transversely of saidhousing, a terminal mounted within each of said portions, a -conductive,elongated mounting member, and resilient, conductive arms being arms forconcentrating at the intermediatearm portions.

forces originating in the spaced ends of said arms when her additionallyhaving a substantially transverse portion engaging said housingportions, and said transverse por-' tion having means for engaging agrounding conductor,

whereby said prong can be connected to said mounting member arms for agrounding connection with'said conductor.

2. An electrical wiring device adapted for reception of a plug having agrounding prong, said device comprising an elongated housing havingspaced projecting portions extending transversely of said housing, aterminal mounted within each of said portions, a conductive, elongatedmounting member, and resilient arms being positioned longitudinally ofsaid mounting member, said arms being spaced adjacent one end thereofand aligned with the insertional path of said prong and being inproximity to one another adjacent their opposite ends, means for joiningsaid arms at their proximate portions to said mounting member, means onsaid housing portions positioned against an intermediate portion of eachof said arms for concentrating at those portions forces originating inthe spaced ends of said arms when said prong is inserted therebetween.

3. An electrical wiring device adapted for reception of a plug having agrounding prong, said device comprising an elongated unitary insulativehousing having spaced elongated portions and having an elongated channelextending in length between said spaced housing portions from one endthereof to the other end thereof and extending in depth from a rear sidethereof to an inner surface of a front housing Wall, an elongatedgrounding mounting member having an elongated portion located in saidchannel adjacent said inner wall surface and having respective mountingears extending longitudinally outward of the ends of said housing, meansfor supporting said mounting member relative to said housing, a pair ofarms spaced laterally of said mounting member and extendingsubstantially perpendicularly rearwardly from said mounting memberadjacent one end of said channel, an elongated crossplate bridging saidarms laterally of said mounting member and being secured to said arms,the opposite end portions of said crossplate extending beyound thelaterally outer arm sides, respectively, said crossplate end portionsmatingly supported in respective guide groves opposingly located in saidspaced housing portions and extending from said rear housing sidesubstantially perpendicularly toward said front housing wall, and meansfor engaging a wire with said crossplate.

4. An electrical wiring device adapted for reception of a plug having agrounding prong, said device comprising an elongated unitary insulativehousing having spaced elongated portions and having an elongated channelextending in length between said spaced housing portions from one endthereof to the other end thereof and extending in depth from a rear sidethereof to an inner surface of a front housing wall, an elongatedgrounding mounting member having an elongated portion located in saidchannel adjacent said inner wall surface and having respective mountingears extending longitudinally outward of the ends of said housing, meansfor supporting said mounting member relative to said housing, at leastone arm extending substantially perpendicularly rearwardly from saidmounting member adjacent one end of said channel, an elongatedcrossplate extending across said arm laterally of said mounting memberand being secured to said arm, the opposite end portions of saidcrossplate extending beyond the laterally outer sides of said arm,respectively, said crossplate end portions matingly supported inrespective guide grooves opposingly located in said spaced housingportions and extending from said rear housing side substantiallyperpendicularly toward said front housing wall, and means for engaging aWire with said crossplate.

References (Iited in the file of this patent UNITED STATES PATENTS1,648,797 Cohen et al Nov. 8, 1927 1,915,070 Muldoon June 20, 19331,927,245 Russell Sept. 19, 1933 2,519,121 Del Camp Aug 15, 19502,686,297 Hutt Aug. 10, 1954 2,890,265 Smith June 9, 1959 2,974,301Slater Mar. 7, 1961

